Refs #22993 -- Removed skipIfCustomUser per deprecation timeline.

django/contrib/auth/tests/utils.py

-import warnings
-from unittest import skipIf
-
-from django.conf import settings
-from django.utils.deprecation import RemovedInDjango20Warning
-
-
-def skipIfCustomUser(test_func):
-    """
-    Skip a test if a custom user model is in use.
-    """
-    warnings.warn(
-        "django.contrib.auth.tests.utils.skipIfCustomUser is deprecated.",
-        RemovedInDjango20Warning, stacklevel=2)
-
-    return skipIf(settings.AUTH_USER_MODEL != 'auth.User', 'Custom user model in use')(test_func)

docs/releases/2.0.txt

@@ -259,3 +259,5 @@ these features.
   zones no longer convert aware datetimes to naive values in UTC anymore when
   such values are passed as parameters to SQL queries executed outside of the
   ORM, e.g. with ``cursor.execute()``.
+
+* ``django.contrib.auth.tests.utils.skipIfCustomUser()`` is removed.